This invention relates generally to multi-line switching valves. Protection of combat vehicle crews against chemical warfare agents requires that air entering the vehicle be purified before it enters the crew compartment. Present technology utilizes Whetlerite charcoal to purify the air by adsorption. The Whetlerite charcoal process has numerous disadvantages. One of the most significant of these is that the charcoal bed must be replaced when the charcoal becomes saturated. This places a great logistical burden on military supply lines. To reduce this burden, regenerative air purification technologies have been developed using multiple adsorber beds. Air entering the vehicle is purified by one adsorber bed while other adsorber beds are being regenerated by outgassing by heating or pressure differential techniques. As each bed becomes saturated, a switching valve switches the flow of air to a fresh bed, at the same time switching the contaminated bed to an outlet line in a regeneration configuration. The leading regenerable purification technologies are of the class called regenerative adsorption technologies which include temperature swing adsorption and pressure swing adsorption. Temperature swing adsorption, utilizing below ambient temperatures, is presently a leading technology for advanced collective protection systems for military vehicles.
A problem with regenerative adsorption systems is that they have complicated valving arrangements. A two-bed system requires four valves on the inlet side. These valves allow the inlet process stream to be directed to the proper bed while shutting off the regeneration back flush outlet line. It is known in the art to provide four shutoff valves at the outlet and to simplify the system by utilizing four check valves. An arrangement using two four-way valves is the previous best state-of-the-art. However, controls are still needed to coordinate the action of the two valves. In such a two-valve system, the two valves must act simultaneously to maintain a flow of purified air to the crew compartment. Failure of the two valves to act simultaneously may result in the death of the crew. The objective of the present invention is to remove this safety hazard by providing one multiple switching valve which switches all the bed inlet and outlet lines simultaneously. This significantly increases safety and reliability while decreasing the complexity of the required control logic. It may also reduce the overall weight, power and volume requirements.